The Government pledged to buy $1.5 trillion in mortgage backed securities (MBS) in an effort to capitalize the mortgage market and artificially push rates down. In doing so, they allowed mortgage rates to reach record lows; at times, 30 year mortgages could be found for under 4.5%! The reason they are creeping up now is because while we had these historically low interest rates, many people refinanced their existing mortgages which re-releases new MBS into the market. Even though the government pledged to buy $1.5 trillion in MBS, they simply cannot keep up with the increased supply of MBS on the market. The increased supply of MBS on the market has pushed the prices of MBS down, which in turn increases interest rates.